The GOLD daytime disk scan measurements are used to derive the TDISK data product,
which is the effective disk neutral temperature at a height of approximately 150 km. TDISK is derived
for each valid dayside Level 1C pixel for approximately 68 disk scan measurements performed per day
by GOLD in nominal operation.
Algorithm heritage
The retrieval algorithm is an extension of those previously used to derive temperature from limb
measurements of LBH intensity from the HITS instrument (Aksnes et al., [2006]; Krywonos et al. [2012]).
Algorithm theoretical basis
GOLD measurements have a higher signal-to-noise ratio than HITS and a spectral range that includes
more of the total N2 LBH emission (132 – 162 nm). Effective neutral temperatures near ~150 km altitude
are retrieved by fitting the observed rotational structure of the N2 LBH bands using an optimal
estimation routine. Retrieved parameters also include the upper vibrational level (v’=0-6) relative
intensities (i.e. populations), a constant background, wavelength shift, and wavelength dispersion
(constant term).
References
Aksnes, A., R. Eastes, S. Budzien, and K. Dymond (2006), Neutral temperatures in the lower thermosphere
from N2 Lyman-Birge-Hopfield (LBH) band profiles, Geophys. Res. Lett., 33, L15103, doi:10.1029/2006GL026255.
Krywonos, A., D. J. Murray, R. W. Eastes, A. Aksnes, S. A. Budzien, and R. E. Daniell (2012), Remote
sensing of neutral temperatures in the Earth’s thermosphere using the Lyman-Birge-Hopfield bands of N2:
Comparisons with satellite drag data, J. Geophys. Res., 117, A09311, doi:10.1029/2011JA017226.
Version:2.3.1
The GOLD daytime disk scan measurements are used to derive the TDISK data product,
which is the effective disk neutral temperature at a height of approximately 150 km. TDISK is derived
for each valid dayside Level 1C pixel for approximately 68 disk scan measurements performed per day
by GOLD in nominal operation.
Algorithm heritage
The retrieval algorithm is an extension of those previously used to derive temperature from limb
measurements of LBH intensity from the HITS instrument (Aksnes et al., [2006]; Krywonos et al. [2012]).
Algorithm theoretical basis
GOLD measurements have a higher signal-to-noise ratio than HITS and a spectral range that includes
more of the total N2 LBH emission (132 – 162 nm). Effective neutral temperatures near ~150 km altitude
are retrieved by fitting the observed rotational structure of the N2 LBH bands using an optimal
estimation routine. Retrieved parameters also include the upper vibrational level (v’=0-6) relative
intensities (i.e. populations), a constant background, wavelength shift, and wavelength dispersion
(constant term).
References
Aksnes, A., R. Eastes, S. Budzien, and K. Dymond (2006), Neutral temperatures in the lower thermosphere
from N2 Lyman-Birge-Hopfield (LBH) band profiles, Geophys. Res. Lett., 33, L15103, doi:10.1029/2006GL026255.
Krywonos, A., D. J. Murray, R. W. Eastes, A. Aksnes, S. A. Budzien, and R. E. Daniell (2012), Remote
sensing of neutral temperatures in the Earth’s thermosphere using the Lyman-Birge-Hopfield bands of N2:
Comparisons with satellite drag data, J. Geophys. Res., 117, A09311, doi:10.1029/2011JA017226.
| Role | Person | |
|---|---|---|
| 1. | PrincipalInvestigator | spase://SMWG/Person/Richard.Eastes |
| 2. | MetadataContact | spase://SMWG/Person/James.M.Weygand |
GOLD web page with news and other information.
Eastes, R.W., McClintock, W.E., Burns, A.G. et al. Space Sci. Rev. (2017) vol. 212, pp.383.
FTP access to Gold tdisk Level L2 data
HTTP access to Gold tdisk Level L2 data
Wavelength grid for N2_LBH mask.
Effective altitude of retrieved temperature.
Retrieval lookup table filename.
Random uncertainty in retrieved neutral temperature.
Retrieved wavelength stretch parameter in each pixel.
GOLD channel (‘A’ or ‘B’).
Pixel latitude.
Tdisk data quality index (GOLD Public Science Data Products Guide).
UTC start time of scan, e.g., "2017-06-21T23:46:38.015Z".
Pixel solar zenith angle.
Systematic uncertainty in retrieved neutral temperature.
Retrieved neutral temperature.
UTC date/time string: "2017-06-21T23:46:38.015Z".
Retrieved background per pixel.
Retrieved wavelength shift parameter in each pixel.
Pixel longitude.
Retrieved temperature vibrational populations.
L1C file name for each occultation.
Pixel emission angle (relative to zenith).
TDISK data quality index per pixel (GOLD Public Science Data Products Guide).
Wavelength mask defining LBH bandpass used in retrieval.
UTC stop time of scan, e.g., "2017-06-21T23:46:38.015Z".
Model uncertainty in retrieved neutral temperature.
Hemisphere scanned (‘N’ or ‘S’).